Panasonic TX-L50BL6E led driver fault

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  • dicky96
    Sun Seeker
    • Mar 2017
    • 1825
    • Spain
    #1

    Panasonic TX-L50BL6E led driver fault

    Hi guys I got this Panasonic TX-L50BL6E Smart TV here. I was given this, it has been left outside an apartment in the garden for several months as it had developed a power supply fault

    Anyway it doesn't seem to be particularly worse for the exposure to the elements, it only rained once here since march.

    The fault is a short circuit on the LED driver board TNPS5914.

    Interestingly someone has tried to repair this before as two legs of one of the power FETs (Q9804) had been unsoldered from the PCB and were floating in mid air but the short is actually on the parallel connected FET Q9802 which is s/c source-drain. It seems odd (to me) if someone could diagnose the fault that far, then why couldn't they figure the short was on the parallel connected FET?

    The problem I have is correctly identifying the power FET it is ST brand and marked

    17NF
    641BT336

    Part number 17NF seems to be a partial part number for an N-MOSFET

    Does someone have a schematic or know the correct part number for Q9802?

    Pics attached

    Thanks
    Rich.
    Attached Files
    Last edited by dicky96; 10-04-2018, 05:11 AM.
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    • vinceroger69
      Badcaps Legend
      • Mar 2012
      • 6714
      • uk
      #2
      Re: Panasonic TX-L50BL6E led driver fault

      in the service manual page 39
      https://www.manualslib.com/manual/12...=39&term=Q9802
      the part is a B1CFRM000028
      https://encompass.com/item/9586854/P.../B1CFRM000028/

        Comment

        • dicky96
          Sun Seeker
          • Mar 2017
          • 1825
          • Spain
          #3
          Re: Panasonic TX-L50BL6E led driver fault

          Hmm Interesting.....

          When I google 'B1CFRM000028 datasheet' one of the first results is '17NF25 MOSFET'
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            Comment

            • vinceroger69
              Badcaps Legend
              • Mar 2012
              • 6714
              • uk
              #4
              Re: Panasonic TX-L50BL6E led driver fault

              on ebay theirs a few listings for, STMicroelectronics STD17NF25 N-channel MOSFET 17 A 250 V but i notice some are 20 amp versions to i did see this on another site too
              Make : ST

              Package : DPAK | TO252
              Marking : 17NF25
              PI Part No : B1CFRM000028
              Part No : STD17NF25
              Part Name : Mosfet Transistor | N-channel 250 V 0.14 Ω typ. Power MOSFET in DPAK
              Last edited by vinceroger69; 10-04-2018, 09:00 AM.

                Comment

                • jetadm123
                  Badcaps Legend
                  • Feb 2010
                  • 2169
                  #5
                  Re: Panasonic TX-L50BL6E led driver fault

                  The B1CFRM000028 is a panasonic internal part number. Could be STD17N25 mosfet? However, the datasheet for the STD17N25 shows that the marking on the mosfet should show 17NF25.
                  Last edited by jetadm123; 10-04-2018, 08:19 AM.

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